以亚硝氮为唯一氮源生长的海洋紫色硫细菌去除无机三态氮

【目的】揭示以亚硝氮为唯一氮源生长的海洋紫色硫细菌去除水体中无机三态氮的特征和规律。【方法】在光照厌氧环境下,以乙酸盐为唯一有机物,在分别以氨氮、亚硝态氮、硝态氮为唯一氮源和三氮共存的模拟水体中,采用Nessler’s试剂分光光度法、N-(1-萘基)-乙二胺分光光度法和紫外分光光度法分别测定水体中氨氮、亚硝态氮和硝态氮的含量,比浊法测定菌体生物量。【结果】随着时间的延长,海洋紫色硫细菌Marichromatium gracile YL28分别在氨氮、亚硝态氮和硝态氮为唯一氮源的水体中对三氮的去除量增加,生物量增大,水体pH升高,并逐渐趋于平衡;YL28对氨氮的最大去除量和最大耐受浓度分别为9.64 mmol/L和36.64 mmol/L,当氨氮浓度低于3.21 mmol/L时,去除率可达97.61%以上;与氨氮相比,以亚硝态氮和硝态氮为唯一氮源,菌体的生长速率、生物量和水体最终pH较低,但对亚硝态氮和硝态氮的去除速率和去除量仍然很高,当亚硝态氮和硝态氮浓度分别达13.50 mmol/L和22.90 mmol/L时,YL28仍能够完全去除。在三氮共存的水体中,YL28也能良好的去除无机三态氮,对亚硝态氮和硝态氮去除能力更强。【结论】在模拟水体中,海洋紫色硫细菌YL28能够分别以氨氮、亚硝态氮和硝态氮为唯一氮源生长,具有良好的耐受和去除无机三态氮的能力,尤其对亚硝态氮具有良好的去除能力。本研究为进一步开发高效脱氮,尤其是去除亚硝态氮的不产氧光合细菌水质调节剂奠定了基础,也为微生物制剂的合理应用提供参考。     

Thiocapsa halophila sp. nov., a new halophilic phototrophic purple sulfur bacterium

A new phototrophic sulfur bacterium has been isolated from a red layer in a laminated mat occurring underneath a gypsum crust in the mediterranean salterns of Salin-de-Giraud (Camargue, France). Single cells were coccus-shaped, non motile, without gas vacuoles and contained sulfur globules. Bacteriochlorophyll a and okenone were present as major photosynthetic pigments. These properties and the G+C content of DNA (65.9–66.6 mol% G+C) are typical characteristics of the genus Thiocapsa. However, the new isolate differs from known species in the genus, particularly in NaCl requirement (optimum, 7% NaCl; range, 3–20% NaCl) and some physiological characteristics. Therefore, a new species is proposed, Thiocapsa halophila, sp. nov.Dedicated to Prof. Dr. Norbert Pfennig in occasion of his 65th birthday     

<Emphasis Type="Italic">Thiocapsa imhoffii</Emphasis>, sp. nov., an alkaliphilic purple sulfur bacterium of the family <Emphasis Type="Italic">Chromatiaceae</Emphasis> from Soap Lake,Washington (USA)

An alkaliphilic purple sulfur bacterium, strain SC5, was isolated from Soap Lake, a soda lake located in east central Washington state (USA). Cells of strain SC5 were gram-negative, non-motile, and non-gas vesiculate cocci, often observed in pairs or tetrads. In the presence of sulfide, elemental sulfur was deposited internally. Liquid cultures were pink to rose red in color. Cells contained bacteriochlorophyll a and spirilloxanthin as major photosynthetic pigments. Internal photosynthetic membranes were of the vesicular type. Optimal growth of strain SC5 occurred in the absence of NaCl (range 0–4%), pH 8.5 (range pH 7.5–9.5), and 32°C. Photoheterotrophic growth occurred in the presence of sulfide or thiosulfate with only a limited number of organic carbon sources. Growth factors were not required, and cells could fix N₂. Dark, microaerobic growth occurred in the presence of both an organic carbon source and thiosulfate. Sulfide and thiosulfate served as electron donors for photoautotrophy, which required elevated levels of CO₂. Phylogenetic analysis placed strain SC5 basal to the clade of the genus Thiocapsa in the family Chromatiaceae with a 96.7% sequence similarity to its closest relative, Thiocapsa roseopersicina strain 1711^T (DSM217^T). The unique assemblage of physiological and phylogenetic properties of strain SC5 defines it as a new species of the genus Thiocapsa, and we describe strain SC5 herein as Tca. imhoffii, sp. nov.     

Phylogenetic characterization of the purple sulfur bacterium Thiocapsa sp. BBS by analysis of the 16S rRNA, cbbL, and nifH genes and its description as Thiocapsa bogorovii sp. nov., a new species

Strain BBS, the purple sulfur bacterium assigned initially to the species Thiocapsa roseopersicina, is the best studied representative of this species. However, no molecular phylogenetic analysis has been performed to confirm its systematic position. Based on the results of analysis of the sequences of 16S rRNA, cbbL, and nifH genes, DNA-DNA hybridization with the T. roseopersicina type strain, and comparative analysis of the phenotypic characteristics of various species belonging to the genus Thiocapsa, we suggest that strain BBS should be assigned to a new species of the genus Thiocapsa, Thiocapsa bogorovii sp. nov. Original Russian Text ? T.P. Tourova, O.I. Keppen, O.L. Kovaleva, N.V. Slobodova, I.A. Berg, R.N. Ivanovsky, 2009, published in Mikrobiologiya, 2009, Vol. 78, No. 3, pp. 381–392.     

Characterization of a new platelet-forming purple sulfur bacterium,Amoebobacter pedioformis sp. nov.

The dominant purple sulfur bacterium of a reddish-colored waste water pond near Taichung, Taiwan, was isolated in pure culture, strain CML2. Individual cells were nearly spherical, nonmotile, and contained in their peripheral parts was vacuoles that appeared like elongated, curved tubes. Four to sixteen cells formed platelet-like aggregates reminiscent of Thiopedia rosea. The intracellular photosynthetic membrane system of the cells was of vesicular type; the photosynthetic pigments consisted of bacteriochlorophyll a and spirilloxanthin as the major carotenoid. The color of cell suspensions was pink to rosered. Under anaerobic conditions photolithoautotrophic growth occurred with sulfide, elemental sulfur or thiosulfate; sulfur globules were stored as an intermediary oxidation product. In the presence of sulfide, acetate, lactate and pyruvate were photoassimilated; strain CML2 lacked assimilatory sulfate reduction. Fastest photoautotrophic growth (11 h doubling time) was obtained at pH 7.5, 35°C and a light intensity of about 1000 lux (tungsten lamp). Chemolithoautotrophic growth in the dark was possible under reduced oxygen partial pressure with reduced sulfur compounds as respiratory substrates. The DNA base composition of strain CML2 was 65.5 mol% G+C. Strain CML2 is described as type strain of a new species, Amoebobacter pedioformis sp. nov., in the family Chromatiaceae.     

Ectothiorhodospira marismortui sp. nov., an obligately anaerobic,moderately halophilic purple sulfur bacterium from a hypersaline sulfur spring on the shore of the Dead Sea

A novel type of purple sulfur bacterium was isolated from a hypersaline sulfur spring on the shore of the Dead Sea. The cells of the isolate are irregularly rod-shaped or curved, and motile by means of a tuft of polar flagella. The photosynthetic system, containing bacteriochlorophyll a and carotenoids of the spirilloxanthin series, is located on stacks of lamellar membranes in the cell cytoplasm. The organism can grow either photoautotrophically with sulfide as electron donor, which is oxidized via extracellular sulfur to sulfate, or photoheterotrophically, using acetate, succinate, fumarate, malate or pyruvate as carbon sources. The bacterium is obligately anaerobic, and requires a source of reduced sulfur for growth. The isolate is moderately halophilic, and grows optimally at NaCl concentrations between 3 and 8%, temperatures between 30 and 45°C, and neutral pH. 16S ribosomal RNA oligonucleotide cataloging suggests a close relationship to purple sulfur bacteria of the genus Ectothiorhodospira. As the isolate differs greatly from the described members of the genus Ectothiorhodospira, we describe the isolate as a new species, and propose the name Ectothiorhodospira marismortui sp. nov.     

Iron sulfur proteins of the purple sulfur bacterium Ectothiorhodospira shaposhnikovii

In addition to several cytochromes three iron sulfur proteins were detected in mixotrophically grown cells of Ectothiorhodospira shaposhnikovii, a member of the Chromatiaceae. They were identified as a bacterial ferredoxin and two high potential iron sulfur proteins (HIPIPs). The two HIPIPs were purified and characterized. They were named according to their differing retention times on a DEAE-cellulose column using a continuous NaCl gradient: early and late HIPIP. The HIPIPs contain 4 mol of non-heme iron and 4 mol of acid labile sulfur per mol protein. Under the conditions of purification the early HIPIP (E _{m, 7}+270 mV) was present in a semi-reduced state. Using ion-exchange chromatography the early HIPIP could be split into a reduced green-brown (pI=3.7) and an oxidized red-brown (pI=3.9) fraction. The late HIPIP (pI=3.8) showed a midpoint potential of only+155 mV, the lowest redox potential of a HIPIP described so far.Non-common abbreviations HIPIP high potential iron sulfur protein - MOPS 3(N-morpholino)propane sulfonate - SDS sodium dodecylsulfate     

Distribution of iron in Lake Banyoles in relation to the ecology of purple and green sulfur bacteria

The distribution of iron both in suspended sediment and in the water column has been studied during summer stratification in Lake Banyoles. In this lake, near bottom springs, a very fine material suspended sediment remains in suspension. Dissolved Fe²⁺ in interstitial water of this suspended sediment, is related to redox potential and to the bottom water inflow. In the water column, soluble iron is present in the hypolimnion of the six different basins forming Lake Banyoles. Under those conditions Fe²⁺ is partially removed by sulfide produced in the anoxic sediment. In addition, a peak of Fe²⁺ found at the density gradient level in basins C-III, C-IV and C-VI. A three compartment model on the dynamics of the processes involving iron in Lake Banyoles is proposed. The bottom springs supply oxygen to the anoxic hypolimnion affecting chemical processes of the iron cycle. The presence of phototrophic sulfur bacteria in the anoxic monimolimnion of basins C-III and C-IV can be related to the kinetics of Fe²⁺ and sulfide. In C-III sulfide concentration exceeds Fe²⁺ concentration whereas in C-IV sulfide is not detectable and iron reached values up to 60 mM. The presence of phototrophic sulfur bacteria in iron-containing environments with no detectable sulfide is explained by the ability of such microorganisms to use FeS as electron donor instead of H₂S.     

Growth and metabolism of the purple sulfur bacterium Thiocapsa roseopersicina under combined light/dark and oxic/anoxic regimens

The dominant purple sulfur bacterium of laminated sediment ecosystems in temperate environments, Thiocapsa roseopersicina, was cultivated in sulfide-limited continuous cultures (D=0.03 h^-1) subjected to various combined diel regimen of aeration and illumination in order to simulate environmental conditions in microbial mats. For comparison, cultures were grown under similar illumination regimens but continuously anoxic conditions.Bacteriochlorophyll a (BChla) and carotenoid synthesis was restricted to anoxic-dark periods and did not occur during oxic-light periods. An increase in the length of the oxic-light periods resulted in decreased pigment contents. However, phototrophic growth remained possible even at 20 h oxic-light/4 h anoxic-dark regimens. When anoxic conditions were maintained throughtout, BChla synthesis occurred both during light and dark periods.Glycogen was synthesized in the light and degraded in the dark. Calculations showed that degradation of 1/4–1/5 of the glycogen is sufficient to account for the BChla and carotenoid synthesis in the dark.The data showed that T. roseopersicina is very well adapted to cope with the combined oxygen and light regimes as they occur in microbial mats, which may explain the dominance of this bacterium in the purple layer of these sediment ecosystems.Non-standard abbreviations BChl bacteriochlorophyll - specific growth rate - D dilution rate - S_R concentration of limiting substrate in reservoir bottle     

一株高含玫红品的红树林海洋紫色硫细菌分离鉴定及特性

摘要:【目的】挖掘我国海洋紫色硫细菌物种资源、深入理解紫色硫细菌在红树林生态系统中的作用。【方法】采用琼脂振荡稀释法、显微技术、紫外可见吸收光谱法、TLC、HPLC 和MS 法。【结果】从福建泉州洛阳桥红树林潮间带泥水样分离获得一株细胞内含多个硫粒的细菌菌株,光合内膜呈囊状、含细菌叶绿素a 和螺菌黄质系类胡萝卜素,结合16S rRNA 基因序列分析和系统发育分析,表明该菌株属于海洋着色菌属(Marichromatium)。该菌株细胞球杆状;最适pH 范围5.7－6.7;最适盐度范围2%－3.5%;温度范围20℃ －35℃;能耐受3.6 mmol/L 硫化物;主要积累玫红品类胡萝卜素,而不是螺菌黄质;3 种细菌叶绿素组分中,一种为BChl aP,另2 种未见报道;不需要生长因子;可光同化固定CO2、能很好利用多种有机酸盐、多价态氮化物和硫化物,尤其能利用柠檬酸、葡萄糖、蔗糖、果糖和丙醇;对氯霉素、头孢唑林、苯、对羟基联苯、恩诺沙星、啶虫脒、HgCl2 和CdCl2的IC50 值分别为70、100、20、20、3、170、5 mg /L和25 mg/L。【结论】该菌株是一株轻度耐酸、高含玫红品类胡萝卜素的紫色硫细菌,被鉴定为Marichromatium gracile 新菌株,编号YL28。该菌株具有广泛利用多种碳源、氮源和硫源物质的能力,对抗生素氯霉素和头孢唑啉、农药啶虫脒、重金属汞和镉具有较强耐受性,对抗生素恩诺沙星较敏感。     

A gas vesiculate planktonic strain of the purple non-sulfur bacterium Rhodoferax antarcticus isolated from Lake Fryxell, Dry Valleys, Antarctica

A moderately psychrophilic purple non-sulfur bacterium, Rhodoferax antarcticus strain Fryx1, is described. Strain Fryx1 was isolated from the water column under the ice of the permanently frozen Lake Fryxell, Antarctica. Cells of Fryx1 are long thin rods and contain gas vesicles, the first report of such structures in purple non-sulfur bacteria. Gas vesicles are clustered at 2–4 sites per cell. Surprisingly, the 16S rRNA gene sequence of strain Fryx1 is nearly identical to that of Rfx. antarcticus strain AB, a short, vibrio-shaped phototroph isolated from an Antarctic microbial mat. Although showing physiological parallels, strains AB and Fryx1 differ distinctly in their morphology and absorption spectra. DNA–DNA hybridization shows that the genomes of strains AB and Fryx1 are highly related, yet distinct. We conclude that although strains AB and Fryx1 may indeed be the same species, their ecologies are quite different. Unlike strain AB, strain Fryx1 has adapted to a planktonic existence in the nearly freezing water column of Lake Fryxell.Dedicated to Prof. Dr. Hans Günter Schlegel on the occasion of his 80th birthday.     

Production of elemental sulfur by green and purple sulfur bacteria

The utilization of sulfide by phototrophic sulfur bacteria temporarily results in the accumulation of elemental sulfur. In the green sulfur bacteria (Chlorobiaceae), the sulfur is deposited outside the cells, whereas in the purple sulfur bacteria (Chromatiaceae) sulfur is found intracellularly. Consequently, in the latter case, sulfur is unattainable for other individuals. Attempts were made to analyze the impact of the formation of extracellular elemental sulfur compared to the deposition of intracellular sulfur.According to the theory of the continuous cultivation of microorganisms, the steady-state concentration of the limiting substrate is unaffected by the reservoir concentration (S _R).It was observed in sulfide-limited continuous cultures ofChlorobium limicola f.thiosulfatophilum that higherS _R values not only resulted in higher steady-state population densities, but also in increased steady-state concentrations of elemental sulfur. Similar phenomena were observed in sulfide-limited cultures ofChromatium vinosum.It was concluded that the elemental sulfur produced byChlorobium, althouth being deposited extracellularly, is not easily available for other individuals, and apparently remains (in part) attached to the cells. The ecological significance of the data is discussed.Non-standard abbreviations RP reducing power - BChl bacteriochlorophyll - N_cell cell material - specific growth rate - {ie52-1} maximal specific growth rate - D dilution rate - K _s saturation constant - s concentration of limiting substrate - S _R same ass but in reservoir bottle - Y yield factor - iS^o intracellular elemental sulfur - eS^o extracellular elemental sulfur - PHB poly-beta-hydroxybutyric acid     

Rhodotorula lamellibrachii sp. nov., a new yeast species from a tubeworm collected at the deep-sea floor in Sagami Bay and its phylogenetic analysis

A new species of the genus Rhodotorula was isolated from a tubeworm (Lamellibrachia sp.) collected at a depth of 1156 m in Sagami Bay, Japan. Strain SY-89 had physiological properties quite similar to R. aurantiaca. Two phylogenetic trees, one based on internal transcribed spacer (ITS) regions and 5.8S rDNA sequences and the other based on the D1/D2 region of the large subunit (26S) rDNA sequences, united strain SY-89 to the type strain of Sakaguchia dacryoides through a considerable evolutionary distance. Strain SY-89 was differentiated from S. dacryoides by the G+C content of the nuclear DNA and differences in the ability to utilize specific carbon and nitrogen compounds. The low complementarity of strain SY-89 DNA to that of the type strain of S. dacryoides confirmed that this strain was genetically unrelated to previously known species. The tubeworm isolates are described as R. lamellibrachii sp. nov. The type strain of R. lamellibrachii is strain SY-89 (= JCM 10907). R. lamellibrachii formed a cluster with Erythrobasidium hasegawianum, R. lactosa, S. dacryoides and Sporobolomyces elongatus on the ITS and 5.8S rDNA phylogenetic tree. These five species shared a signature sequence in 26S rDNA, although this relationship was not supported by phylogeny based on the D1/D2 region of 26S rDNA.     

Localization of hydrogenase in the purple sulphur bacterium Thiocapsa roseopersicina

The localization of hydrogenase in the phototrophic bacterium Thiocapsa roseopersicina was investigated by subcellular fractionations, and transmission electron microscopic immunocytochemistry. By using sonicated cells and measuring in vitro hydrogenase activities in soluble and membrane fractions, respectively, a weak hydrophobic interaction between the hydrogenase enzyme and the T. roseopersicina membranes was observed. Polyclonal antisera directed against the purified hydrogenase were raised in rabbits and exhibited one band in native-PAGE/Western immunoblot analysis. Native-PAGE/activity stain confirmed the identity of this band as being hydrogenase. Immunocytolocalization experiments using ultrathin sections showed an internal localization of the hydrogenase enzyme. A higher specific labeling was associated with chromatophores, indicating a possible coupling of hydrogenase with the photosynthetic membranes in the T. roseopersicina cells.     

A new purple sulfur bacterium from saline littoral sediments,Thiorhodovibrio winogradskyi gen. nov. and sp. nov.

Two strains of a new purple sulfur bacterium were isolated in pure culture from the littoral sediment of a saline lake (Mahoney Lake, Canada) and a marine microbial mat from the North Sea island of Mellum, respectively. Single cells were vibrioid-to spirilloid-shaped and motile by means of single polar flagella. Intracellular photosynthetic membranes were of the vesicular type. As photosynthetic pigments, bacteriochlorophyll a and the carotenoids lycopene, rhodopin, anhydrorhodovibrin, rhodovibrin and spirilloxanthin were present.Hydrogen sulfide and elemental sulfur were used under anoxic conditions for phototrophic growth. In addition one strain (06511) used thiosulfate. Carbon dioxide, acetate and pyruvate were utilized by both strains as carbon sources. Depending on the strain propionate, succinate, fumarate, malate, tartrate, malonate, glycerol or peptone may additionally serve as carbon sources in the light. Optimum growth rates were obtained at pH 7.2, 33 °C, 50 mol m^-2 s^-1 intensity of daylight fluorescent tubes and a salinity of 2.2–3.2% NaCl. During growth on sulfide, up to ten small sulfur globules were formed inside the cells. The strains grew microaerophilic in the dark and exhibited high specific respiration rates. No vitamins were required for growth. The DNA base composition was 61.0–62.4 mol% G+C.The newly isolated bacterium belongs to the family chromatiaceae and is described as a member of a new genus and species, Thiorhodovibrio winogradskyi gen. nov. and sp. nov. with the type strain SSP1, DSM No. 6702.     

Specific detection of an oil-degrading bacterium, Corynebacterium sp. IC10, in sand microcosms by PCR using species-specific primers based on 16S rRNA gene sequences

A species-specific PCR technique to detect an oil-degrading bacterium, Corynebacterium sp. IC10, released into sand microcosms is described. PCR primers, specific to strain IC10, were designed based on 16S rRNA gene sequences and tested against both closely and distantly related bacterial strains using four primer combinations involving two forward and two reverse primers. Two sets of them were specific to the strain IC10 and Corynebacterium variabilis and one set was selected for further analysis. The PCR amplification was able to detect 1 pg template DNA of strain IC10 and 1.2×10⁴ c.f.u. of IC10 ml wet sand^–1 in the presence of 3×10⁸ Escherichia coli cells. In non-sterile sand microcosms seeded with the strain IC10, the sensitivity of detection decreased to 9.6×10⁵ c.f.u. ml wet sand^–1. The detection sensitivity thus depends on the complexity of background heterogeneous DNA of environmental samples. The assay is suitable for detection of Corynebacterium sp. IC10 in laboratory microcosms, however, cross reaction with non-oil degrading coryneforms may prohibit its use in uncharacterized systems.     

Nickel requirement for the formation of active urease in purple sulfur bacteria (Chromatiaceae)

Nickel was found to be required for expression of urease activity in batch cultures of Thiocapsa roseopersicina strain 6311, Chromatium vinosum strain 1611 and Thiocystis violacea strain 2311, grown photolithotrophically with NH₄Cl as nitrogen source. In a growth medium originally free of added nickel and EDTA, the addition of 0.1–10 M nickel chloride caused an increase in urease activity, while addition of EDTA (0.01–2 mM) caused a strong reduction. Variation of the nitrogen source had no pronounced influence on the level of urease activity in T. roseopersicina grown with 0.1 M nickel in the absence of EDTA. Only nickel, of several heavy metal ions tested, could reverse suppression of urease activity by EDTA. Nickel, however, did not stimulate and EDTA did not inhibit the enzyme in vitro. When nickel was added to cultures already growing in a nickel-deficient, EDTA-containing medium, urease activity showed a rapid increase which was not inhibited by chloramphenicol. It is concluded that the (inactive) urease apoprotein may be synthesized in the absence of nickel and can be activated in vivo without de novo protein synthesis by insertion of nickel into the pre-formed enzyme protein.     

<Emphasis Type="Italic">Chlorobaculum macestae</Emphasis> sp. nov., a new green sulfur bacterium

The investigated green sulfur bacterium, strain M, was isolated from a sulfidic spring on the Black Sea Coast of the Caucasus. The cells of strain M are straight or curved rods 0.6–0.9 × 1.8–4.2 μm in size. According to the cell wall structure, the bacteria are gram-negative. Chlorosomes are located along the cell periphery. Strain M is an obligate anaerobe capable of photoautotrophic growth on sulfide, thiosulfate, and H₂. Acetatate is utilized as an additional carbon source. It utilizes ammonium, urea, casein hydrolysate, and N₂ as nitrogen sources and sulfide, thiosulfate, and elemental sulfur as sulfur sources. Bacteriochlorophyll c and the carotenoid chlorobactene are the main pigments. The optimal growth temperature is 25–28°C; the optimal pH is 6.8. The strain does not require NaCl. Vitamin B 12 stimulates growth. The content of the G+C base pairs in the DNA of strain M is 58.3 mol %. In the phylogenetic tree constructed on the basis of analysis of nucleotide sequences of 16S rRNA genes, strain M forms a separate branch, which occupies an intermediate position between the phylogenetic cluster containing representatives of the genus Chlorobaculum (94.9–96.8%) and the cluster containing species of the genus Chlorobium (94.1–96.5%). According to the results of analysis of the amino acid sequence corresponding to the fmo gene, strain M represents a branch which, unlike that in the “ribosomal” tree, falls into the cluster of the genus Chlorobaculum (95.8–97.2%). Phylogenetic analysis of the amino acid sequence corresponding to the nifH gene placed species of the genera Chlorobaculum and Chlorobium into a single cluster, whereas strain M formed a separate branch. The results obtained allow us to describe strain M as a new species of the genus ChlorobacChlorobaculum — Chlorobaculum macestae sp. nov.